Astrononion
Genus of single-celled organisms
From Wikipedia, the free encyclopedia
Astrononion is a genus of foraminifera in the family Nonionidae, characterized by an evolute planispiral test with radially stellate structures partly covering the sutures on either side. The test is free, bilaterally symmetrical; periphery broadly rounded; chambers distinct, separated by depressed radial sutures, increasing gradually in size, and usually inflated; aperture a low arched opening at the base of the face of the test. The wall is of finely perforate monolamellar granular calcite.
| Astrononion Temporal range: M Eocene - Recent | |
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| Genus: | Astrononion Cushman & Edwards, 1937 |
The secondary chamberlets in the original description of Cushman and Edwards 1937 that give the stellate appearance were noted by Loeblich and Tappan as resulting from non-porous flaps that project backwards from each chamber partly covering the preceding suture and umbilical region but leaving a small open cavity beneath, giving the appearance of secondary chamberlets.
Astrononion has a cosmopolitan distribution and is known from the Middle Eocene to the recent. Along with Fujinonion, Laminononion, and Pacinonion, it forms the subfamily Astononioninae.